The present invention generally relates to a tactile sensor, and a method to tactilely sense, and more specifically, to a tactile sensor and method to tactilely sense which may not be affected by the application of pressure applied to the sensor by the environment in which the sensor may be located.
The ability to sense touch may be of particular importance for tasks such as close-up assembly work, where vision may be obscured by objects, or may not be possible due to an absence of light or other conditions. Touch may by used to provide sensory feedback necessary for griping or sensing objects, determining the orientation of objects, and the like. Touch may be sensed using a tactile sensor. A tactile sensor may be incorporated on, for example, remote control vehicles, robots, and/or may be utilized as tamper warning devices, or other such warning devices on various machines, systems, and the like.
Various systems may be used to tactically sense an object. Tactile sensors may include, for example, elastomeric skins embodying conductive elements, piezoelectric elastomers, and/or deformable skins comprising semi-conductive coils that may be actuated through application of pressure, and which may provide electrical or other feedback signals representative of an object being sensed. Such feedback may then be further manipulated or used by various systems to which a tactile sensor may be in communication with.
To operate properly in some systems, tactile sensors may be required to be sensitive to various forms of touch such that an application of pressure to the sensor actuates the sensor to provide feedback. However, the environment in which the sensor may be located may also apply a force to the sensor. The sensor may thus be required to be actuated upon application of a touching force that may be less than a force that may be applied to the sensor by the environment in which the sensor may be located. Such a condition may exist, for example, in a system using a tactile sensor operated below water, in particular, at depths approaching 50 or more feet under water. To counteract such an environmental force, the tactile sensor may need to include a static or fixed bias against such a force, and/or made less sensitive to overcome such environmental forces. Thus, to overcome a pressure exerted on a tactile sensor by an external environment, a tactile sensor may lack sensitivity desired for a particular application.
When an environmental pressure that may be applied to a sensor by an external environment results in a reduction of applied force, a tactile sensor may also not operate properly. For example, should a tactile sensor be operated at an altitude typical for aircraft operation, the external environment may apply less pressure on the sensor than would be applied to the sensor if the aircraft were at ground level. The environmental pressures may thus require a greater force to be applied to the tactile sensor to achieve the same result as would a lesser force applied at a higher environmental pressure. As such, a sensor at high altitudes may lack sensitivity in a desired range, or may not function at all.
As can be seen, there is a need for a tactile sensor that may not be impacted by the external environment in which the sensor may be expected to operate. Further, there is a need for a tactile sensor that may be used in environments above atmospheric pressure, in environments below atmospheric pressure, and which may provide various forms of feedback representative of a spatial arrangement of an object that may be sensed.